A cauldron is a giant, iron pot that witches use in the creation of potions. These potions serve a variety of purposes, and it was customary for any self respecting witch to own one since the old days for containing their mixtures. However, they come with several disadvantages.

Cauldrons are large and expensive, making them difficult to store as they take up much room. Their size also makes them difficult to transport from place to place. As they are mostly immobile, cauldrons are location specific, limiting their use. The iron involved in their construction also rusts over time, making them improper for doing potions long term.

The expense in maintaining cauldrons along with their other drawbacks makes them impractical for modern use compared to more recent items. These days, their are newer, cheaper ways of making and storing these liquids that entrepreneurial witches can take advantage of to save on cost. I need a way to make cauldrons a staple of witchcraft despite there being other competing solutions. How can they stay relevant in the modern world?

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    $\begingroup$ Iron doesn't have to rust if maintained. See all the cast iron skillet aficionados. $\endgroup$ – jdunlop Jun 10 '20 at 17:07
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    $\begingroup$ @jdunlop Ironically, some of the best reasonings for a good cast iron skillet would very easily transfer to the potion making in this scenario. "Even heating means that meats brown better and vegetables cook faster without having to constantly manage the heat source or rotate pans in the oven. Cast iron is ideal for frying and baking because it holds and distributes heat so well." $\endgroup$ – IT Alex Jun 10 '20 at 19:42
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    $\begingroup$ I think it was Shakespeare who linked witches to cauldrons. I've never known a witch with one. $\endgroup$ – NomadMaker Jun 10 '20 at 23:43
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    $\begingroup$ @NomadMaker read more Eastern European mythology. Baba Yaga flies around in a mortar and pestal, and that evolves into cauldron in some venues. $\endgroup$ – SRM Jun 11 '20 at 0:08
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    $\begingroup$ @SRM I thought about Baba Yaga. I like her living quarters, not so much her diet. But in the stories I've read it's always been flying in a mortar and pestle. I blame Shakespeare for the evolution to the caldron. $\endgroup$ – NomadMaker Jun 11 '20 at 0:20

16 Answers 16


OPTION A: Iron is to magic what lead is to nuclear reactors

The idea of iron, being a magic blocking element is a pretty common trope originating from old fairy-tails that sometimes mention a material called "cold iron" as a way of killing faerie folk. Since then, iron has been the element of choice for countless authors when it comes to killing and binding various kinds of magical creatures. Many RPGs even forbid the use of iron based armor for magical classes because it blocks the flow of magic.

So if you are trying to use magic, why would you want something that blocks it? The answer is simple, you need to contain it. When you are making a potion, every ingredient you add changes what sort of magic is happening in your cauldron. While your end result might be a harmless love potion, the intermediate stages might contain all sorts of magic that can cause vomiting, diarrhea, paralysis, green skin, warts, sore throat, stuttering, changes in blood viscosity and color, water allergies, changes in buoyancy, extra nipples, or even death. So, to prevent errant magics from getting out of the pot and harming the witch, he/she uses a pot made out of thick iron to block any magical energies that could seep through and effect him/her during the process. Thinner pots or pots made out of other materials simply allow the magical energies of unstable potion states to radiate through affecting the witch.

If you want to go with the idea of cold-iron as opposed to any old iron, your primitive looking cauldrons work even better. One common interpretation of what "cold-iron" was is that it was iron that has never been heated to a liquid form. Prior to the late medieval period, most forges were bloomery forges. They were not hot enough to liquefy iron all the way, so "cold iron" could have been ore that was heated up to cherry red, and was then hammered, folded, and hammered some more until all the impurities were pressed out of it. This process often created complex crystalline structures in your iron like you see in pattern-welded, Damascus, or folded steel blades. In contrast, modern iron is pretty exclusively crucible steel which means it is fully melted, sifted for impurities, and then poured into a form; so, it by it's nature has a very simple crystalline structure. If the crystalline structure of forged iron is somehow important to the containment of magic, then typical modern metallurgy becomes useless, and all of your cauldrons will still need to be hand crafted artisan pieces.

As for competing solutions

If you go really high tech, modern meta-material research can create complex microscopic patterns in all sorts of materials. Science could replicate and even improve on the crystal patterns of cold iron by laser etching thousands of sheets of thin laminated iron filament and kiln forging them together. In doing so you could make much thinner and more portable cauldrons, but setting up high-tech meta-material labs is very expensive; so, while light weight portable potion pots could exist, the they would be much more expensive even than the hand-crafted alternative.

OPTION B: The cauldron is the sacred icon of Cerridwen

When you trace the history of the cauldron in witchcraft back to its origins you arrive at the Welsh goddess Cerridwen. Cerridwen was the goddess of the moon, prophecy, magic, death, and rebirth and the cauldron was her sacred icon. There are a few Welsh tails centered around the use of cauldrons tapping into the divine power of Cerridwen which was likely the inspiration for Shakespear's witches in Macbeth which really popularized the trope.

If you go this way, it is not the pot, its contents, or the witch who is actually doing the magic, but the goddess Cerridwen bestowing divine gifts on the contents of the cauldron. By using a cauldron, you are effectively praying over an alter you've made to the goddess showing your reverence for her. The size and cost of one's cauldron shows the goddess your devotion to her; so, giant cauldrons are basically just used as a symbol of adoration to gain her favor.

One could in theory pray over any old pot, and it might work if you've already proven yourself to the goddess, but most witches only use cauldrons when asking thier goddess for favors out of respect.

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    $\begingroup$ Ask a question about folklore, get an answer straight from folklore. This is a really good answer. $\endgroup$ – Fivesideddice Jun 11 '20 at 0:44
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    $\begingroup$ Side effects may include: green skin, diarrhea, vomiting, paralysis, death, and warts. Get your order correct 😉. $\endgroup$ – Matthew Jun 11 '20 at 1:21
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    $\begingroup$ @Matthew don't forget water allergy. $\endgroup$ – John Dvorak Jun 11 '20 at 5:07
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    $\begingroup$ Don't lean over your cauldron while stirring unless you want a blast of magic in the face! Perhaps that causes deformity and warts. $\endgroup$ – Chris H Jun 12 '20 at 11:20
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    $\begingroup$ Related: You need the iron to contain the magic so it doesn't escape from whatever you're making. $\endgroup$ – Loren Pechtel Jun 13 '20 at 3:10

Surviving Cauldrons are Powerful Artifacts.

In the Golden Era of witchcraft, a big iron cauldron was an expensive thing to create. The largest and wealthiest covens might have an iron cauldron; but a smaller coven would have to negotiate using someone else's. There were never more than a thousand cauldrons in existence, and those were passed down from generation to generation, over the centuries.

Over the course of hundreds of years of brewing, magical potions sink into the metal and permeate the object. The cauldron slowly acquires a magical power of its own that makes it almost indestructible, and improves the potency of potions brewed in it.

Thus the original thousand cauldrons still play an important role in modern witchcraft. Every cauldron used by a modern coven is hundreds of years old. They all have proper names (usually names after the most famous past owner) and your everyday witch (or protagonist?) can make it big by stumbling upon an undiscovered cauldron buried in the earth.

  • $\begingroup$ Related: Continuing to brew your potions in the same cauldron over time causes your cauldron to become magical and enhance what you're making. $\endgroup$ – Loren Pechtel Jun 13 '20 at 3:12
  • $\begingroup$ @LorenPechtel: That's what I mean -- it improves the potency of the potions. $\endgroup$ – Daron Jun 13 '20 at 13:55
  • $\begingroup$ I'm saying that even without there only being ancient cauldrons the same idea could apply. $\endgroup$ – Loren Pechtel Jun 13 '20 at 20:06
  • $\begingroup$ @LorenPechtel. You're right. What I'm proposing is that the process occur slowly enough that any cauldron that has absorbed a significant amount of power has to be a big old-fashioned metal one. $\endgroup$ – Daron Jun 13 '20 at 20:23
  • $\begingroup$ @LorenPechtel You could start today with your smallest cooking pot, and your great-great-grandchildren would eventually inherit a saucepan of power +3. But for selfish reasons people don't do this much, and instead just keep using the old cauldrons. $\endgroup$ – Daron Jun 13 '20 at 20:25

Law of Similarity, the great rule of magic. Like produces like.

If you knock out a potion using a cheap, mass-market pot, you end up with a weak potion. A strong, sturdy cauldron lends your potion strength, and its immobility makes the potion's effects harder to be removed by outside influences, and its age makes the potion last longer


It is not the cauldron. It is the fire.

Cauldrons are for making potions. But really what is doing a lot of the work making a potion is the fire. For ideal potions this cannot be an electrical coil or a gas jet or some other source of heat - it has to be a fire, with flame, and the things that are burning to make those flames matter almost as much as the things that go into the cauldron.

Cooking a liquid over an open flame pretty much requires a pot of some sort and cauldrons work well. The problem with scaling things down to, say, a Dutch oven or smaller pot is that potions often call for entire creatures or organs to be added and they are of a fixed size. Adding just a portion of a live creature is not the same.

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    $\begingroup$ I think you've generally got a good idea here, but I would add two things. First, the material of the cauldron may matter (it's magic, after all). Note that this implies that some potions require a copper cauldron, or a cauldron made of specific types of stone. (And yes, the fuel would also matter!) Second, a large cauldron is a significant heat sink; just like a dutch oven, it will resist rapid changes in temperature. Just as in cooking, this might be critical for certain potions, especially ones that call for adding ingredients that must be cold or frozen immediately prior to addition. $\endgroup$ – Matthew Jun 10 '20 at 17:34
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    $\begingroup$ Fire is a rather wild heat source. It can vary in temperature quite quickly as it grows and dies with fuel, A thick cauldron made of iron is what allows the most delicate of recipes to be achieved. If a recipe says to keep it perfectly heated for 10 minutes at 275 and you have a flimsy stainless steel cauldron it would be rather hard to maintain a uniform, constant temperature with the ease of which it can transfer heat. $\endgroup$ – IT Alex Jun 10 '20 at 19:41
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    $\begingroup$ @ITAlex, ooh, right, I hadn't thought about the temperature of the heat source being unstable. That's an excellent point! If you combine that with needing to burn certain materials (i.e. can't just use gas or electricity), then a large, thick cauldron with a lot of heat capacity becomes almost mandatory. Or, at minimum, a lot easier to work with compared to something smaller and thinner. (Huh, now I'm imagining brewing potions in/over a baine-marie 😉.) $\endgroup$ – Matthew Jun 11 '20 at 1:27
  • $\begingroup$ @ITAlex Won't the fact that most potions liquid and likely water-based take care of most of the temperature modulation? Once you've got the cauldron at a boil, the temperature of the liquid cannot go above 100C. Boiling liquids are already at a constant temperature, regardless of their container. $\endgroup$ – Nuclear Hoagie Jun 11 '20 at 13:59
  • $\begingroup$ @NuclearWang only if you are using thin recipes instead of something that is thicker like molasses or honey. Even then, the temperature modulation of the fire would introduce the changes in temperature quicker than a cast iron cauldron. It would be hard to constantly toil and trouble while feeding your fire for delicate recipes. $\endgroup$ – IT Alex Jun 11 '20 at 14:27

From a purely scientific standpoint, we now know that the purpose of the cauldron is to serve as an energy sink. The thick dense metal absorbs any residual magical energy which might be left over from recent spell casting along with the natural spillage from any nearby ley lines. Such random energies can play havoc with the magically sensitive ingredients which are required by most effective potions. A good cauldron absorbs all uninvited energies into itself, keeping everything but the fire's heat from getting inside.

To function properly, a cauldron has to be large enough to neutralize whatever level of magic is likely to be present at potion making time. That is why large covens and powerful lone witches have large cauldrons while lesser witches, either alone or in triad unions can suffice with the smaller portable models.

Those semi-insane techmages over on the west coast have been experimenting with combining faraday's cages and warding circles, and they have had some interesting results, but for safety and dependability, nothing beats a good old fashioned cauldron.

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    $\begingroup$ Cast iron, since it is thermally, well stable, also resits temperature changes for whatever is cooking inside. It's why crock pot and dutch oven cooked stews always taste best. $\endgroup$ – Paul TIKI Jun 10 '20 at 23:02

The power of traditions, like in any good self respecting form of cult.

"This is how it was done, and this is how you will do it", it doesn't matter if you can microwave a potion in few seconds instead of stirring it in the cauldron.

It can be applied to food making, liquors brewing, religions... why should witchcraft be different?

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    $\begingroup$ And of course, when the main character decides to go experimenting with these techniques, he's shunted from their society, despite figuring out how to make potions for a tenth the cost anyone else can. I like it. $\endgroup$ – Sanford Bassett Jun 10 '20 at 15:52
  • $\begingroup$ It could be a rite of passage, the final test as a Magnum Opus. Craft your own cauldron and brew your most difficult potion. $\endgroup$ – Gustavo Jun 10 '20 at 17:52
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    $\begingroup$ @gustavo like the final test of a Jedi: making a lightsaber. $\endgroup$ – SRM Jun 11 '20 at 0:14

Resonating Chamber

If magical energy had a wave nature, then if something reflected those waves and that something was the right size, then there could standing waves of magic energy, creating a resonance effect. This resonance could then make the magic far more potent than it would be otherwise.

So the cauldron acts like a Helmholtz Resonator.

The boundary between the air and the potion could also be reflective, adding to the resonance.


Drastically different take here that kind of challenges your premise a bit at first, but bear with me.

The cauldron itself is only an accessory to the spellcasting, acting as a catalyst.

Perhaps it makes it easier to concentrate the magic required for producing the potions, or maybe it's a meditation aid that simplifies focusing your mind in the way required to actually prepare the spell used to actually prepare the potion. The exact details don't really matter and can just be fluff for the story. The important thing is just that using a cauldron makes it easier to do the actual magic.

Once you're there, it's simple to extrapolate that the mark of a truly skilled or powerful witch is that they don't actually need a big iron cauldron. Such individuals are rare though, so your everyday witch who needs to do any kind of serious potion making (that is, non-trivial potions, or production of very large batches of simple ones) just uses one all the time because they'll need it anyway for the big stuff, so there's no point in not using it for the little things.

You can reinforce this logic though by leaning on psychology (or, as it's alternately known in this context to the witches of Terry Pratchett's Discworld 'headology' or 'Boffo', I very much recommend reading some of his books that follow the witches because they do a great job of explaining this through demonstration). In effect, everybody expects witches to have a big iron cauldron, so the witches oblige and play the part because:

  1. It's good advertising. You've got all the hallmarks of being a witch, ergo everybody treats you like one. This makes setting up in a new area or dealing with new people much simpler.
  2. It has somewhat of a placebo effect due to confirmation bias. IOW, because everybody knows witches know what they're doing when it comes to healing potions, obviously something a witch gives you and tells you is a healing potion has to work, because they know what they're talking about. This, in turn, can feed further back into both itself and the advertising aspect.

Putting all this together, you end up with a situation where every witch has a cauldron because no self-respecting witch wouldn't have a cauldron, even if they don't actually need a cauldron.


Volume is important

Potions involve a great deal of reduction, siphoning off elements you don't want or need, concentrating elements you want lots of.

Ultimately, you need a great volume of liquid to work with, and it's far more convenient to have it all in one place.

An ultra-modern potion-maker might use vats and keep their ingredients in factory-scale bulk, use centrifuges to isolate the elements they need. But that needs infrastructure that a hedge-witch doesn't have. So a big metal bowl isn't going to go out of fashion any time soon.


The age and condition of the cauldron is already incorporated into the spell and potion making.

Both the rust, and accumulated grime and magical residue from repeated uses are ingredients in the magic. Spells and potions take, and even demand certain condition cauldrons, into consideration for gaurenteed results.

While modern day witches might be able to quantify the amount of rust/iron to add to a spell/potion to modernise the process, the magical residue and age pattenas are something that hasnt been successfully replicated in the spotless stainless steel modern witches kitchens...yet. reworking the 1000 year old recipes for modern cauldrons is going to take some time.

Variations of POTION RECIPES

  • one large 10 year old partially rusted cauldron
  • 1 small - medium well aged cauldron in good condition. (Only slight age discoloration allowed or else potion potency cannot be guaranteed).
  • 1 pot with no previous history of making class 5 potions or above
  • 1 medium partially maintained pot with several years of adept potion making imbued in the rim. Bottom of pot must be well scoured.

It's also why any well-versed witch has several cauldrons on hand. Also why while sharing pots isn't exactly prohibited, it's not considered best practise. You definitely don't want to inherit the magical residue from the neighbour who blew themselves up last week!


Iron oxide is toxic, but like all toxins it's dose dependent. Therefore one could build a strong tolerance to some toxins over time by consuming smaller amounts of that same substances.

Maybe your witches like to drink the blood of young virgins so they remain younger or don't age....whatever, make up something...maybe they just like to eat children's liver and bone marrow.

Blood, liver and bone marrow are highly toxic for a normal person because of the high quantities of iron, but someone who is used to the toxicity of iron can tolerate it. That's why some people get sick from eating blood while others can tollerate it, the same reason a chickens liver doesn't kill you but no one can eat a bear's liver and survive.

By natural selection witches using rusty dirty and old cauldrons build up a tolerance to iron and are able to eat more children/drink more blood and live longer.

While the witches using modern tech don't build that same tolerance to iron.

Also, no ....eating veggies high in iron doesn't build iron tollerance because vegetal iron is already filtered out by the body when in excess.


For the record, you can buy small cauldrons, about 4 inches in diameter. You might have the traditional large cauldrons be used in a single location (the witch's kitchen which would parallel their traditional use on the hearth) or be reserved for the use of a coven. Individual witches could use the smaller cauldrons. Also, many potions (just like cooking) give better results when the ingredients are simmered together for a while, rather than throwing them all in a bowl and putting them in the microwave. Also, think about cast iron pots, which are seasoned over time and that lends a flavor to what is cooked in it. Sometimes it might be about convenience and then a microwave mix might do, but there are advantages to sticking with a cauldron. Also, cauldrons can be used for purposed other than mixing a potion -- you can burn something in a cauldron without catching your house on fire. Chanting over burning ingredients (or when stirring - think Macbeth) is another venue where cauldrons work better than microwaves or stovetops.


Cauldrons are large and expensive, making them difficult to store as they take up much room. Their size also makes them difficult to transport from place to place. As they are mostly immobile, cauldrons are location specific, limiting their use.

Sometimes you just need to have a log of liquid in a place from where you won't be leaving for a while. That's why even though beer cans have been a thing for quite long, kegs are still a thing.

The iron involved in their construction also rusts over time, making them improper for doing potions long term.

As other have said, the iron is the secret ingredient in the stronger potions.

The expense in maintaining cauldrons along with their other drawbacks makes them impractical for modern use compared to more recent items. These days, their are newer, cheaper ways of making and storing these liquids that entrepreneurial witches can take advantage of to save on cost.

That does not happen with potions only. It's with everything.

There are some american wines that sell for under three dollars a bottle. But if you've ever tasted real wine (even the cheap ones that go for 40 USD a bottle), you'll never want to come within a foot of distance from the bootleg stuff. That's because plastic will never age wine like a cask will, and that's why most of the money in the industry goes to wineries and not prison gangs.

I need a way to make cauldrons a staple of witchcraft despite there being other competing solutions. How can they stay relevant in the modern world?

It's all about a market niche. Yeah Alley Sally sells flu cures at \$1 a plastic bottle, but all that bisphenol A will destroy your gonads in a couple years. I wish to stay healthy for the foreseaable future, so I'll still be paying $60 on an iron flask at the local apothecary.


Size and metallurgy could play a role in this process.


Google up images of camp fire pots, most of these are for cooking over a camp fire usually suspended over the fire with sticks or metal rods. They aren't much bigger then a normal stove top pot. So smaller size means more portable, easy to bring out into the woods or over to a coven meeting, hell you can have 3 or 4 potions on an electric stove going at the same time.


Others here allude to things like recipes and things like "cold iron" as relates to magic. But we can go the other route, new cauldrons and potions might do better in different containers. Stainless steel (no rust), aluminum (weight), etc. Most of the time "fancy" tools engraved on the outside, but this is witch craft; perhaps new cauldrons have engravings on the inside. Maybe those engravings are lined with special materials for purity or magic.

"Use a silver inlaid cauldron to maximize the purity of this process."


It's a status symbol

Only the wealthy or well-established witches have cauldrons.

Sure, you could make it in a fancy new scientific material or a small container... but you're not seen as a committed witch. The flimsy stuff is for the hobbyists; the cauldron is for the real witches.


Well, Cerridwen used the cauldron, so it's become quite a bit of a symbol to have something that hearkens back to the source.

Due to this, the elite witchcraft supply builders put their best materials into their cauldron models, because they know that the elite (or wannabe elite) witches will buy the cauldrons and expect it to be the best.

(This answer is a riff off of two other answers.)


Thermal mass.

Cast iron has a lot of thermal mass, which is great for evening out fluctuations in the heat source and maintaing a steady temperature of the contents. The traditional fire is not a very stable heat source, so cast iron cauldrons helped to keep the heat on the potion constant.

Better technology can give more stable heat sources, which wouldn't require a heavy cast-iron vessel to make your potions in, but you might not own one. You might have improvised your heating setup with cheap electric hotplates that turn on and off a couple of times per minute, and thus need the thermal mass of a cast-iron cauldron if you want to produce anything decent.

As for why you'd want a big cauldron, simple volume. If you sell 50 litres of burn-treatment a month, you'd want a big cauldron to brew a big batch in, so you can minimise the time you spend on brewing popular potions. Just a matter of how much you sell and how long it keeps that determines how big a cauldron you use to brew it. The traditional witch probably had a few sizes of cast-iron cauldron, but the big one just stuck in everyone's mind because it was so unusual to see one that big.


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